//package com.useek.lx.utils;
//import java.io.UnsupportedEncodingException;
//
//public class Base64 {
//    /**
//     * Default values for encoder/decoder flags.
//     */
//    public static final int DEFAULT = 0;
// 
//    /**
//     * Encoder flag bit to omit the padding '=' characters at the end
//     * of the output (if any).
//     */
//    public static final int NO_PADDING = 1;
// 
//    /**
//     * Encoder flag bit to omit all line terminators (i.e., the output
//     * will be on one long line).
//     */
//    public static final int NO_WRAP = 2;
// 
//    /**
//     * Encoder flag bit to indicate lines should be terminated with a
//     * CRLF pair instead of just an LF.  Has no effect if {@code
//     * NO_WRAP} is specified as well.
//     */
//    public static final int CRLF = 4;
// 
//    /**
//     * Encoder/decoder flag bit to indicate using the "URL and
//     * filename safe" variant of Base64 (see RFC 3548 section 4) where
//     * {@code -} and {@code _} are used in place of {@code +} and
//     * {@code /}.
//     */
//    public static final int URL_SAFE = 8;
// 
//    /**
//     * Flag to pass to {@link Base64OutputStream} to indicate that it
//     * should not close the output stream it is wrapping when it
//     * itself is closed.
//     */
//    public static final int NO_CLOSE = 16;
// 
//    //  --------------------------------------------------------
//    //  shared code
//    //  --------------------------------------------------------
// 
//    /* package */ static abstract class Coder {
//        public byte[] output;
//        public int op;
// 
//        /**
//         * Encode/decode another block of input data.  this.output is
//         * provided by the caller, and must be big enough to hold all
//         * the coded data.  On exit, this.opwill be set to the length
//         * of the coded data.
//         *
//         * @param finish true if this is the final call to process for
//         *        this object.  Will finalize the coder state and
//         *        include any final bytes in the output.
//         *
//         * @return true if the input so far is good; false if some
//         *         error has been detected in the input stream..
//         */
//        public abstract boolean process(byte[] input, int offset, int len, boolean finish);
// 
//        /**
//         * @return the maximum number of bytes a call to process()
//         * could produce for the given number of input bytes.  This may
//         * be an overestimate.
//         */
//        public abstract int maxOutputSize(int len);
//    }
// 
//    //  --------------------------------------------------------
//    //  decoding
//    //  --------------------------------------------------------
// 
//    /**
//     * Decode the Base64-encoded data in input and return the data in
//     * a new byte array.
//     *
//     * <p>The padding '=' characters at the end are considered optional, but
//     * if any are present, there must be the correct number of them.
//     *
//     * @param str    the input String to decode, which is converted to
//     *               bytes using the default charset
//     * @param flags  controls certain features of the decoded output.
//     *               Pass {@code DEFAULT} to decode standard Base64.
//     *
//     * @throws IllegalArgumentException if the input contains
//     * incorrect padding
//     */
//    public static byte[] decode(String str, int flags) {
//        return decode(str.getBytes(), flags);
//    }
// 
//    /**
//     * Decode the Base64-encoded data in input and return the data in
//     * a new byte array.
//     *
//     * <p>The padding '=' characters at the end are considered optional, but
//     * if any are present, there must be the correct number of them.
//     *
//     * @param input the input array to decode
//     * @param flags  controls certain features of the decoded output.
//     *               Pass {@code DEFAULT} to decode standard Base64.
//     *
//     * @throws IllegalArgumentException if the input contains
//     * incorrect padding
//     */
//    public static byte[] decode(byte[] input, int flags) {
//        return decode(input, 0, input.length, flags);
//    }
// 
//    /**
//     * Decode the Base64-encoded data in input and return the data in
//     * a new byte array.
//     *
//     * <p>The padding '=' characters at the end are considered optional, but
//     * if any are present, there must be the correct number of them.
//     *
//     * @param input  the data to decode
//     * @param offset the position within the input array at which to start
//     * @param len    the number of bytes of input to decode
//     * @param flags  controls certain features of the decoded output.
//     *               Pass {@code DEFAULT} to decode standard Base64.
//     *
//     * @throws IllegalArgumentException if the input contains
//     * incorrect padding
//     */
//    public static byte[] decode(byte[] input, int offset, int len, int flags) {
//        // Allocate space for the most data the input could represent.
//        // (It could contain less if it contains whitespace, etc.)
//        Decoder decoder = new Decoder(flags, new byte[len*3/4]);
// 
//        if (!decoder.process(input, offset, len, true)) {
//            throw new IllegalArgumentException("bad base-64");
//        }
// 
//        // Maybe we got lucky and allocated exactly enough output space.
//        if (decoder.op == decoder.output.length) {
//            return decoder.output;
//        }
// 
//        // Need to shorten the array, so allocate a new one of the
//        // right size and copy.
//        byte[] temp = new byte[decoder.op];
//        System.arraycopy(decoder.output, 0, temp, 0, decoder.op);
//        return temp;
//    }
// 
//    /* package */ static class Decoder extends Coder {
//        /**
//         * Lookup table for turning bytes into their position in the
//         * Base64 alphabet.
//         */
//        private static final int DECODE[] = {
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
//            52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -1, -1,
//            -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
//            15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
//            -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
//            41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//        };
// 
//        /**
//         * Decode lookup table for the "web safe" variant (RFC 3548
//         * sec. 4) where - and _ replace + and /.
//         */
//        private static final int DECODE_WEBSAFE[] = {
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1,
//            52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -1, -1,
//            -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
//            15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63,
//            -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
//            41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
//        };
// 
//        /** Non-data values in the DECODE arrays. */
//        private static final int SKIP = -1;
//        private static final int EQUALS = -2;
// 
//        /**
//         * States 0-3 are reading through the next input tuple.
//         * State 4 is having read one '=' and expecting exactly
//         * one more.
//         * State 5 is expecting no more data or padding characters
//         * in the input.
//         * State 6 is the error state; an error has been detected
//         * in the input and no future input can "fix" it.
//         */
//        private int state;   // state number (0 to 6)
//        private int value;
// 
//        final private int[] alphabet;
// 
//        public Decoder(int flags, byte[] output) {
//            this.output = output;
// 
//            alphabet = ((flags & URL_SAFE) == 0) ? DECODE : DECODE_WEBSAFE;
//            state = 0;
//            value = 0;
//        }
// 
//        /**
//         * @return an overestimate for the number of bytes {@code
//         * len} bytes could decode to.
//         */
//        public int maxOutputSize(int len) {
//            return len * 3/4 + 10;
//        }
// 
//        /**
//         * Decode another block of input data.
//         *
//         * @return true if the state machine is still healthy.  false if
//         *         bad base-64 data has been detected in the input stream.
//         */
//        public boolean process(byte[] input, int offset, int len, boolean finish) {
//            if (this.state == 6) return false;
// 
//            int p = offset;
//            len += offset;
// 
//            // Using local variables makes the decoder about 12%
//            // faster than if we manipulate the member variables in
//            // the loop.  (Even alphabet makes a measurable
//            // difference, which is somewhat surprising to me since
//            // the member variable is final.)
//            int state = this.state;
//            int value = this.value;
//            int op = 0;
//            final byte[] output = this.output;
//            final int[] alphabet = this.alphabet;
// 
//            while (p < len) {
//                // Try the fast path:  we're starting a new tuple and the
//                // next four bytes of the input stream are all data
//                // bytes.  This corresponds to going through states
//                // 0-1-2-3-0.  We expect to use this method for most of
//                // the data.
//                //
//                // If any of the next four bytes of input are non-data
//                // (whitespace, etc.), value will end up negative.  (All
//                // the non-data values in decode are small negative
//                // numbers, so shifting any of them up and or'ing them
//                // together will result in a value with its top bit set.)
//                //
//                // You can remove this whole block and the output should
//                // be the same, just slower.
//                if (state == 0) {
//                    while (p+4 <= len &&
//                           (value = ((alphabet[input[p] & 0xff] << 18) |
//                                     (alphabet[input[p+1] & 0xff] << 12) |
//                                     (alphabet[input[p+2] & 0xff] << 6) |
//                                     (alphabet[input[p+3] & 0xff]))) >= 0) {
//                        output[op+2] = (byte) value;
//                        output[op+1] = (byte) (value >> 8);
//                        output[op] = (byte) (value >> 16);
//                        op += 3;
//                        p += 4;
//                    }
//                    if (p >= len) break;
//                }
// 
//                // The fast path isn't available -- either we've read a
//                // partial tuple, or the next four input bytes aren't all
//                // data, or whatever.  Fall back to the slower state
//                // machine implementation.
// 
//                int d = alphabet[input[p++] & 0xff];
// 
//                switch (state) {
//                case 0:
//                    if (d >= 0) {
//                        value = d;
//                        ++state;
//                    } else if (d != SKIP) {
//                        this.state = 6;
//                        return false;
//                    }
//                    break;
// 
//                case 1:
//                    if (d >= 0) {
//                        value = (value << 6) | d;
//                        ++state;
//                    } else if (d != SKIP) {
//                        this.state = 6;
//                        return false;
//                    }
//                    break;
// 
//                case 2:
//                    if (d >= 0) {
//                        value = (value << 6) | d;
//                        ++state;
//                    } else if (d == EQUALS) {
//                        // Emit the last (partial) output tuple;
//                        // expect exactly one more padding character.
//                        output[op++] = (byte) (value >> 4);
//                        state = 4;
//                    } else if (d != SKIP) {
//                        this.state = 6;
//                        return false;
//                    }
//                    break;
// 
//                case 3:
//                    if (d >= 0) {
//                        // Emit the output triple and return to state 0.
//                        value = (value << 6) | d;
//                        output[op+2] = (byte) value;
//                        output[op+1] = (byte) (value >> 8);
//                        output[op] = (byte) (value >> 16);
//                        op += 3;
//                        state = 0;
//                    } else if (d == EQUALS) {
//                        // Emit the last (partial) output tuple;
//                        // expect no further data or padding characters.
//                        output[op+1] = (byte) (value >> 2);
//                        output[op] = (byte) (value >> 10);
//                        op += 2;
//                        state = 5;
//                    } else if (d != SKIP) {
//                        this.state = 6;
//                        return false;
//                    }
//                    break;
// 
//                case 4:
//                    if (d == EQUALS) {
//                        ++state;
//                    } else if (d != SKIP) {
//                        this.state = 6;
//                        return false;
//                    }
//                    break;
// 
//                case 5:
//                    if (d != SKIP) {
//                        this.state = 6;
//                        return false;
//                    }
//                    break;
//                }
//            }
// 
//            if (!finish) {
//                // We're out of input, but a future call could provide
//                // more.
//                this.state = state;
//                this.value = value;
//                this.op = op;
//                return true;
//            }
// 
//            // Done reading input.  Now figure out where we are left in
//            // the state machine and finish up.
// 
//            switch (state) {
//            case 0:
//                // Output length is a multiple of three.  Fine.
//                break;
//            case 1:
//                // Read one extra input byte, which isn't enough to
//                // make another output byte.  Illegal.
//                this.state = 6;
//                return false;
//            case 2:
//                // Read two extra input bytes, enough to emit 1 more
//                // output byte.  Fine.
//                output[op++] = (byte) (value >> 4);
//                break;
//            case 3:
//                // Read three extra input bytes, enough to emit 2 more
//                // output bytes.  Fine.
//                output[op++] = (byte) (value >> 10);
//                output[op++] = (byte) (value >> 2);
//                break;
//            case 4:
//                // Read one padding '=' when we expected 2.  Illegal.
//                this.state = 6;
//                return false;
//            case 5:
//                // Read all the padding '='s we expected and no more.
//                // Fine.
//                break;
//            }
// 
//            this.state = state;
//            this.op = op;
//            return true;
//        }
//    }
// 
//    //  --------------------------------------------------------
//    //  encoding
//    //  --------------------------------------------------------
// 
//    /**
//     * Base64-encode the given data and return a newly allocated
//     * String with the result.
//     *
//     * @param input  the data to encode
//     * @param flags  controls certain features of the encoded output.
//     *               Passing {@code DEFAULT} results in output that
//     *               adheres to RFC 2045.
//     */
//    public static String encodeToString(byte[] input, int flags) {
//        try {
//            return new String(encode(input, flags), "US-ASCII");
//        } catch (UnsupportedEncodingException e) {
//            // US-ASCII is guaranteed to be available.
//            throw new AssertionError(e);
//        }
//    }
// 
//    /**
//     * Base64-encode the given data and return a newly allocated
//     * String with the result.
//     *
//     * @param input  the data to encode
//     * @param offset the position within the input array at which to
//     *               start
//     * @param len    the number of bytes of input to encode
//     * @param flags  controls certain features of the encoded output.
//     *               Passing {@code DEFAULT} results in output that
//     *               adheres to RFC 2045.
//     */
//    public static String encodeToString(byte[] input, int offset, int len, int flags) {
//        try {
//            return new String(encode(input, offset, len, flags), "US-ASCII");
//        } catch (UnsupportedEncodingException e) {
//            // US-ASCII is guaranteed to be available.
//            throw new AssertionError(e);
//        }
//    }
// 
//    /**
//     * Base64-encode the given data and return a newly allocated
//     * byte[] with the result.
//     *
//     * @param input  the data to encode
//     * @param flags  controls certain features of the encoded output.
//     *               Passing {@code DEFAULT} results in output that
//     *               adheres to RFC 2045.
//     */
//    public static byte[] encode(byte[] input, int flags) {
//        return encode(input, 0, input.length, flags);
//    }
// 
//    /**
//     * Base64-encode the given data and return a newly allocated
//     * byte[] with the result.
//     *
//     * @param input  the data to encode
//     * @param offset the position within the input array at which to
//     *               start
//     * @param len    the number of bytes of input to encode
//     * @param flags  controls certain features of the encoded output.
//     *               Passing {@code DEFAULT} results in output that
//     *               adheres to RFC 2045.
//     */
//    public static byte[] encode(byte[] input, int offset, int len, int flags) {
//        Encoder encoder = new Encoder(flags, null);
// 
//        // Compute the exact length of the array we will produce.
//        int output_len = len / 3 * 4;
// 
//        // Account for the tail of the data and the padding bytes, if any.
//        if (encoder.do_padding) {
//            if (len % 3 > 0) {
//                output_len += 4;
//            }
//        } else {
//            switch (len % 3) {
//                case 0: break;
//                case 1: output_len += 2; break;
//                case 2: output_len += 3; break;
//            }
//        }
// 
//        // Account for the newlines, if any.
//        if (encoder.do_newline && len > 0) {
//            output_len += (((len-1) / (3 * Encoder.LINE_GROUPS)) + 1) *
//                (encoder.do_cr ? 2 : 1);
//        }
// 
//        encoder.output = new byte[output_len];
//        encoder.process(input, offset, len, true);
// 
//        assert encoder.op == output_len;
// 
//        return encoder.output;
//    }
// 
//    /* package */ static class Encoder extends Coder {
//        /**
//         * Emit a new line every this many output tuples.  Corresponds to
//         * a 76-character line length (the maximum allowable according to
//         * <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>).
//         */
//        public static final int LINE_GROUPS = 19;
// 
//        /**
//         * Lookup table for turning Base64 alphabet positions (6 bits)
//         * into output bytes.
//         */
//        private static final byte ENCODE[] = {
//            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
//            'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
//            'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
//            'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/',
//        };
// 
//        /**
//         * Lookup table for turning Base64 alphabet positions (6 bits)
//         * into output bytes.
//         */
//        private static final byte ENCODE_WEBSAFE[] = {
//            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
//            'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
//            'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
//            'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_',
//        };
// 
//        final private byte[] tail;
//        /* package */ int tailLen;
//        private int count;
// 
//        final public boolean do_padding;
//        final public boolean do_newline;
//        final public boolean do_cr;
//        final private byte[] alphabet;
// 
//        public Encoder(int flags, byte[] output) {
//            this.output = output;
// 
//            do_padding = (flags & NO_PADDING) == 0;
//            do_newline = (flags & NO_WRAP) == 0;
//            do_cr = (flags & CRLF) != 0;
//            alphabet = ((flags & URL_SAFE) == 0) ? ENCODE : ENCODE_WEBSAFE;
// 
//            tail = new byte[2];
//            tailLen = 0;
// 
//            count = do_newline ? LINE_GROUPS : -1;
//        }
// 
//        /**
//         * @return an overestimate for the number of bytes {@code
//         * len} bytes could encode to.
//         */
//        public int maxOutputSize(int len) {
//            return len * 8/5 + 10;
//        }
// 
//        public boolean process(byte[] input, int offset, int len, boolean finish) {
//            // Using local variables makes the encoder about 9% faster.
//            final byte[] alphabet = this.alphabet;
//            final byte[] output = this.output;
//            int op = 0;
//            int count = this.count;
// 
//            int p = offset;
//            len += offset;
//            int v = -1;
// 
//            // First we need to concatenate the tail of the previous call
//            // with any input bytes available now and see if we can empty
//            // the tail.
// 
//            switch (tailLen) {
//                case 0:
//                    // There was no tail.
//                    break;
// 
//                case 1:
//                    if (p+2 <= len) {
//                        // A 1-byte tail with at least 2 bytes of
//                        // input available now.
//                        v = ((tail[0] & 0xff) << 16) |
//                            ((input[p++] & 0xff) << 8) |
//                            (input[p++] & 0xff);
//                        tailLen = 0;
//                    };
//                    break;
// 
//                case 2:
//                    if (p+1 <= len) {
//                        // A 2-byte tail with at least 1 byte of input.
//                        v = ((tail[0] & 0xff) << 16) |
//                            ((tail[1] & 0xff) << 8) |
//                            (input[p++] & 0xff);
//                        tailLen = 0;
//                    }
//                    break;
//            }
// 
//            if (v != -1) {
//                output[op++] = alphabet[(v >> 18) & 0x3f];
//                output[op++] = alphabet[(v >> 12) & 0x3f];
//                output[op++] = alphabet[(v >> 6) & 0x3f];
//                output[op++] = alphabet[v & 0x3f];
//                if (--count == 0) {
//                    if (do_cr) output[op++] = '\r';
//                    output[op++] = '\n';
//                    count = LINE_GROUPS;
//                }
//            }
// 
//            // At this point either there is no tail, or there are fewer
//            // than 3 bytes of input available.
// 
//            // The main loop, turning 3 input bytes into 4 output bytes on
//            // each iteration.
//            while (p+3 <= len) {
//                v = ((input[p] & 0xff) << 16) |
//                    ((input[p+1] & 0xff) << 8) |
//                    (input[p+2] & 0xff);
//                output[op] = alphabet[(v >> 18) & 0x3f];
//                output[op+1] = alphabet[(v >> 12) & 0x3f];
//                output[op+2] = alphabet[(v >> 6) & 0x3f];
//                output[op+3] = alphabet[v & 0x3f];
//                p += 3;
//                op += 4;
//                if (--count == 0) {
//                    if (do_cr) output[op++] = '\r';
//                    output[op++] = '\n';
//                    count = LINE_GROUPS;
//                }
//            }
// 
//            if (finish) {
//                // Finish up the tail of the input.  Note that we need to
//                // consume any bytes in tail before any bytes
//                // remaining in input; there should be at most two bytes
//                // total.
// 
//                if (p-tailLen == len-1) {
//                    int t = 0;
//                    v = ((tailLen > 0 ? tail[t++] : input[p++]) & 0xff) << 4;
//                    tailLen -= t;
//                    output[op++] = alphabet[(v >> 6) & 0x3f];
//                    output[op++] = alphabet[v & 0x3f];
//                    if (do_padding) {
//                        output[op++] = '=';
//                        output[op++] = '=';
//                    }
//                    if (do_newline) {
//                        if (do_cr) output[op++] = '\r';
//                        output[op++] = '\n';
//                    }
//                } else if (p-tailLen == len-2) {
//                    int t = 0;
//                    v = (((tailLen > 1 ? tail[t++] : input[p++]) & 0xff) << 10) |
//                        (((tailLen > 0 ? tail[t++] : input[p++]) & 0xff) << 2);
//                    tailLen -= t;
//                    output[op++] = alphabet[(v >> 12) & 0x3f];
//                    output[op++] = alphabet[(v >> 6) & 0x3f];
//                    output[op++] = alphabet[v & 0x3f];
//                    if (do_padding) {
//                        output[op++] = '=';
//                    }
//                    if (do_newline) {
//                        if (do_cr) output[op++] = '\r';
//                        output[op++] = '\n';
//                    }
//                } else if (do_newline && op > 0 && count != LINE_GROUPS) {
//                    if (do_cr) output[op++] = '\r';
//                    output[op++] = '\n';
//                }
// 
//                assert tailLen == 0;
//                assert p == len;
//            } else {
//                // Save the leftovers in tail to be consumed on the next
//                // call to encodeInternal.
// 
//                if (p == len-1) {
//                    tail[tailLen++] = input[p];
//                } else if (p == len-2) {
//                    tail[tailLen++] = input[p];
//                    tail[tailLen++] = input[p+1];
//                }
//            }
// 
//            this.op = op;
//            this.count = count;
// 
//            return true;
//        }
//    }
// 
//    private Base64() { }   // don't instantiate
//}
package com.bainuo.doctor.common.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;


public class Base64 {
    private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();  
        public static String encode(byte[] data) {
            int start = 0;  
            int len = data.length;  
            StringBuffer buf = new StringBuffer(data.length * 3 / 2);
  
            int end = len - 3;  
            int i = start;  
            int n = 0;  
  
            while (i <= end) {  
                int d = ((((int) data[i]) & 0x0ff) << 16)  
                        | ((((int) data[i + 1]) & 0x0ff) << 8)  
                        | (((int) data[i + 2]) & 0x0ff);  
  
                buf.append(legalChars[(d >> 18) & 63]);  
                buf.append(legalChars[(d >> 12) & 63]);  
                buf.append(legalChars[(d >> 6) & 63]);  
                buf.append(legalChars[d & 63]);  
  
                i += 3;  
  
                if (n++ >= 14) {  
                    n = 0;  
                    buf.append(" ");  
                }  
            }  
  
            if (i == start + len - 2) {  
                int d = ((((int) data[i]) & 0x0ff) << 16)  
                        | ((((int) data[i + 1]) & 255) << 8);  
  
                buf.append(legalChars[(d >> 18) & 63]);  
                buf.append(legalChars[(d >> 12) & 63]);  
                buf.append(legalChars[(d >> 6) & 63]);  
                buf.append("=");  
            } else if (i == start + len - 1) {  
                int d = (((int) data[i]) & 0x0ff) << 16;  
  
                buf.append(legalChars[(d >> 18) & 63]);  
                buf.append(legalChars[(d >> 12) & 63]);  
                buf.append("==");  
            }  
  
            return buf.toString();  
        }  
  
        private static int decode(char c) {  
            if (c >= 'A' && c <= 'Z')  
                return ((int) c) - 65;  
            else if (c >= 'a' && c <= 'z')  
                return ((int) c) - 97 + 26;  
            else if (c >= '0' && c <= '9')  
                return ((int) c) - 48 + 26 + 26;  
            else  
                switch (c) {  
                case '+':  
                    return 62;  
                case '/':  
                    return 63;  
                case '=':  
                    return 0;  
                default:  
                    throw new RuntimeException("unexpected code: " + c);
                }  
        }  
  
        /** 
         * Decodes the given Base64 encoded String to a new byte array. The byte 
         * array holding the decoded data is returned. 
         */  
  
        public static byte[] decode(String s) {
  
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            try {  
                decode(s, bos);  
            } catch (IOException e) {
                throw new RuntimeException();
            }  
            byte[] decodedBytes = bos.toByteArray();  
            try {  
                bos.close();  
                bos = null;  
            } catch (IOException ex) {
                System.err.println("Error while decoding BASE64: " + ex.toString());
            }  
            return decodedBytes;  
        }  
  
        private static void decode(String s, OutputStream os) throws IOException {
            int i = 0;  
  
            int len = s.length();  
  
            while (true) {  
                while (i < len && s.charAt(i) <= ' ')  
                    i++;  
  
                if (i == len)  
                    break;  
  
                int tri = (decode(s.charAt(i)) << 18)  
                        + (decode(s.charAt(i + 1)) << 12)  
                        + (decode(s.charAt(i + 2)) << 6)  
                        + (decode(s.charAt(i + 3)));  
  
                os.write((tri >> 16) & 255);  
                if (s.charAt(i + 2) == '=')  
                    break;  
                os.write((tri >> 8) & 255);  
                if (s.charAt(i + 3) == '=')  
                    break;  
                os.write(tri & 255);  
  
                i += 4;  
            }  
        }  
          
}  